1. Field of the Invention
The present invention relates to a device for rendering jets of water luminous and to installations equipped with such a device, such as for example fountains, shower installations or cascades.
2. Brief Description of the Related Art
Luminous fountains are known which have one or more jets of water equipped with various devices for rendering these jets luminous. Among these devices the most widely known are aerial sources of light or more usually immersed sources of light such as projectors.
In the case of aerial projectors, an illuminated jet of water is but very slightly visible owing to a considerable loss of the light. Indeed, the major part of the light projected in the direction of the jet passes to one side of the latter. Consequently, only a small part of the light energy produced by the projector really serves to light up the jet. This problem can be overcome with specific optical systems associated with the projectors. But such a solution is usually costly and must be designed for each fountain individually. Further, in this case of lighting, only one side of the jet is really lit up. In order to obtain a homogeneous illumination of the jet of water, i.e. an illumination which is such that an observer has an identical impression of the luminous jet wherever he is situated, it is essential to dispose around the jet a set of several projectors.
With an immersed projector, it is possible to somewhat improve the result of the lighting. But it is found that only the lowermost part of the jet is effectively illuminated. In the case of relatively long jets, this solution does not provide a satisfactory result. Also, as in the case of aerial projectors, it is necessary to dispose several projectors around the jet to light up the latter on all sides, which considerably increases the cost of the device.
There is also known from patent FR-A-2 562 637 belonging to the applicants of the present application, a device for rendering jets of water luminous which comprises, for each jet to be illuminated, a light conductor, such as one or more optical fibers, connected to a source of light. The output end of the conductor whose cross section is small relative to the section of the jet, is disposed within the latter. This device provides a homogeneous illumination of the jets. However, the applicants have noticed that this device can only be applied to jets of water no higher than about 0.5 m.
Further, luminous fountains are known which comprise a tank filled with water provided with an opening toward the bottom of its lateral surface. A lens is inserted in the side of the tank opposite the opening. In order to render the stream of liquid issuing from the opening luminous, the latter is illuminated through the liquid by a convergent beam of light rays obtained by means of the inserted lens which is illuminated by an external source of light. Although this known fountain provides a jet of water which is illuminated in a homogeneous manner, it will be understood that such a construction is costly and for example may be difficult to adapt to existing fountains and in particular fountains having vertical jets of water.